For a state that considers itself a hip, progressive trendsetter, California looks like anything but that when you peek inside the executive suites and boardrooms of its 400 largest companies.

Five years after UC Davis initiated the first study of the gender split at the top of corporate California, men still hold nearly nine of every 10 positions, according to the latest survey released today by our Graduate School of Management.

Sadly, the numbers haven't changed much since we began this annual study, which relies on data sifted from mandatory reports to the Securities and Exchange Commission. The data shows that in California's top 400, women hold only 10.6 percent of board seats and executive positions.

Nearly a third - 118 of the top 400 companies in California, the world's eighth-largest economy - do not have a single woman on their board or executive team. Only 15 have a woman CEO.

Surely in a state that elected two women to the U.S. Senate and backed Hillary Rodham Clinton for president, there are more women capable and deserving of top management jobs and boardroom seats.

What little there is to celebrate in this year's report can be found in San Francisco, which has both the top-ranked company - Bare Escentuals - and the highest share - 17.3 percent - of women in top executive positions among counties with 20 or more large firms.

We should salute Bare Escentuals, a cosmetics firm guided by CEO Leslie Blodgett and five women on its board. Bare Escentuals, runner-up to Nara Bancorp in last year's survey, was the only company among the top 400 with women holding fully half of its top executive and board positions.

At the other end, high-tech Silicon Valley and Santa Clara County continue to trail the rest of the state. Not only does Santa Clara County have more of the top 400 - 117 - than any other county, it also has the smallest share, 8.2 percent, of women in its boardrooms.

Silicon Valley executives, who have not been reluctant to push their progressive political ideas, should be able to do better - much better.

Besides the apparent unfairness of it all, and the specter of discrimination, why should we care about this stubborn gender imbalance? For the first time, our study this year starts to address that complicated and contentious question.

There has been evidence for a while to suggest that those firms that are more diverse perform better financially. Now we believe there is some evidence to suggest those firms with more women at the top also might perform better socially.

We compared our list of the top 400 companies to a list compiled by Newsweek magazine and KLD Research & Associates of the 500 largest national firms, ranked according to their commitment to environmentally friendly policies.

Of 62 California firms that made Newsweek's list, those that have both women executives and board members had the best environmental performance. Those that had neither had the worst. Though the study is very preliminary and based on a small sample, the results warrant further study.

So there might be more than simple fairness and equal opportunity at stake here. Companies that have more women at the top, and the viewpoints they bring to the table, might perform better for their shareholders and our environment.